1. Field of the Invention
The present invention relates to apparatus and method of assembling heat exchanging tube for a heat exchanger capable of automatically assembling heat exchanging tubes, which serve as heating tubes, cooling tubes or the like, applied to a heat exchanger (for example, a feed water heater, a boiler, a humidity separating and heating unit, a ground steam evaporator, and a cooling unit for cooling cooling water, condensed water, oil or the like) which is provided with thermal power generation plants, nuclear power generation plants and the like as an accessory.
2. Description of the Related Art
An example of a prior art will be first described with reference to FIG. 19 and FIG. 20. This example relates to an assembly of heat exchanging tubes as heating tubes in a horizontal type feed water heater used in thermal power generation plants, nuclear power generation plants and the like.
FIG. 19 schematically shows how the tubes are assembled to the feed water heater. The feed water heater is generally composed of a cylindrical frame 1 in which accommodated are a multiplicity of U-shaped tubes 2 called heating tubes into which circulating water flows and a tube bundle is formed by the tubes. The respective tubes 2 are assembled by being inserted into the holes 4 of a plurality of partitions 3 disposed in parallel with each other from an open end side with the U-shaped curved portions of the tubes 2 on a bent end side directed longitudinally.
As shown in FIG. 19, the tubes 2 are assembled in such a manner that the base portion 1a of the cylindrical frame 1 is fixed on a height adjustment table 5 as well as the partitions 3 are positioned at a predetermined height by a support table 6 and the tubes 2 are sequentially inserted into the holes 4 of the partitions 3 by the hand work of five to eight workers. After all the tubes 2 are inserted into the holes 4 of the partitions 3, a cylindrical barrel 1b is combined with and welded to the base portion 1a of the cylindrical frame 1 to thereby complete a heat exchanger.
FIG. 20 shows a plan view of the partition 3 described above, FIG. 21 shows the state that the tubes 2 are inserted into the partitions 3 in an enlarged fashion and FIG. 22 shows a side surface shape of the tube 2. As shown in these drawings, the tube bundle is composed to 1000 to 3000 pieces of the tubes 2 in which the tube whose U-shaped curved portion on the bent end side has a minimum radius R is disposed at the center of the partition 3 and both the side portions of the tubes whose U-shaped curved portion has a larger radius R are sequentially disposed above and below the tube (CL in FIG. 21 shows a gap between a first stage and a second stage). In this case, since the tube 2 having a larger radius R covers the end portion of the tube 2 having a smaller radius R on the bent end side, the tube having the smaller radius R is inserted into the partitions 3 first and thereafter the tubes 2 having the larger radius R are sequentially assembled in a usual assembling process for inserting the tubes 2 from the open end side. Conventionally, an assembly job for assembling all the tubes 2 is regularly carried out from the tubes having the smaller radius R to the tubes having the larger radius R according to the above process.
An assembling method according to the above process will be described with reference to FIG. 19. In general, the tubes 2 are separately accommodated in a plurality of packing cases 7 after they are finished. Thus, all the packing cases 7 are piled up with the packing case 7 in which the tubes 2 whose U-shaped curved portion has a minimum radius R are accommodated disposed at an uppermost stage. Thereafter, each of the packing cases 7 is sequentially placed on a work table 8 in the order of the case located on an upper stage to the case located on a lower stage, a lid 7a on the upper surface of the packing case 7 is removed and then all the tubes 2 are lifted and taken out from the packing case 7 using a not shown crane, a hoist beam, a plurality of nylon strings and the like and placed on skids 9 placed on the packing case 7 and the dirt at the extreme ends of the tubes 2 are wiped out.
Thereafter, the five to eight workers lift up the tubes 2 on the skids 9 one by one and align the open ends of the tubes 2 with the holes 4 of the partition 3 and support and insert the tubes 2 while walking and the rearmost worker pushes the tube 2 until the bent end side thereof is fallen into the predetermined place of the partition 3. Before the rearmost worker finishes the pushing job, the foremost worker goes to a rear side and make preparation for the next job by taking up the next tube 2. Thereafter, the tubes 2 of the same radius R are sequentially assembled by the repetition of the above process.
On the completion of the insertion and assembly of the tubes 2 prepared on the skids 9, the tubes 2 of the same type are lifted by the crane, the lift beam, the nylon strings and the like and taken out onto the skids 9 again and the dirt at the extreme ends thereof are wiped out and thereafter jobs similar to the above jobs are carried out.
When the assembly of the tubes 2 having the minimum radius R to the first stage of the holes at the center of the partitions 3 is completed by the repetition of the above jobs, a necessary number of packing cases 7 which accommodate the tubes 2 corresponding to the second stages of the holes located above and below the first stage are prepared and the same jobs are repeated. Thereafter, a predetermined number of the tubes 2 are inserted into the holes 4 of the partitions 3 in the predetermined stages in the order of an odd stage and an even stage by the repetition of the same jobs. At that time, since a gap is necessary to take out the packing cases 7 accommodating the tubes 2 for respective stages, the tubes 2 for the odd stages and tubes 2 for the even stages are separately accommodated in the packing cases 7.
The tube 2 has a length of, for example, about 11 meters and is formed to have a slender shape with a diameter D of about 20 millimeters. Thus, when there are a smaller number of support points, the job for inserting the tube 2 is difficult because the tube 2 is liable to be bent in such a case. Accordingly, there are conventionally required a large number of workers. Further, when the tubes 2 accommodated in the packing case 7 are taken out one by one, it is become difficult to take out the tubes 2 remaining in the packing case 7 because they collapse in the packing case 7. To cope with this problem, a necessary number of the tubes 2 must be previously taken out on the packing case 7, which requires an additional setup job before the insertion of the tubes.
The tubes 2 are regularly disposed in the feed water heater in the order of the tubes 2 having the minimum radius R to the tubes 2 having the maximum radius R as shown in FIGS. 20 to 22. However, since the tubes 2 must be sequentially inserted from the tubes 2 having a smaller radius R due to the characteristics of the U-shape as described above, a multiplicity of the packing cases 7 accommodating the tubes 2 of the same radius R must be prepared. When the tubes 2 having a different radius R are accommodated in the same packing case 7 to enhance the accommodating efficiency of the packing case 7, there arises a disadvantage of the tube 2 having, for example, a small radius and which is taken out from the packing case 7 midway in the above process and the opened packing case 7 must be moved to a different position and temporarily placed there. At the same time, since all the packing cases 7 in which the necessary tubes 2 are accommodated must be opened, a large space is required to temporarily place the opened packing cases.
Further, since the tubes 2 must be conveyed from the packing cases 7 disposed as described above to the work table 8, a job for lifting them by the crane or the like is increased as well as when the crane is used by other job, the tube conveying job must be interrupted. As described above, the assembly of the heat exchanging tubes in heat exchanger executed by the prior art method has various problems such that the tubes are inefficiently assembled because a large number of workers are required and many complicated manual jobs are necessary and the space in which the packing cases are disposed is increased.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art described above and to provide an apparatus and method of assembling a heat exchanging tube in a heat exchanger by which the number of workers can be reduced, complicated manual jobs can be decreased, the working efficiency can be increased and the space in which packing cases are disposed can be reduced in addition to the tubes being securely and easily inserted.
This and other objects can be achieved according to the present invention by providing, in one aspect, a heat exchanging tube assembling apparatus for a heat exchanger having an outer casing in which is arranged partition plate means formed with holes through which heat exchanging tubes, each having a U-shape in an outer appearance, are inserted from an open end side of the casing in a full automatic manner, the heat exchanging tube assembling apparatus comprising:
tube grasping means for grasping a plurality of U-shaped tubes in a lump at a working position;
tube positioning means for positioning the grasped tubes to positions from which the U-shaped tubes are inserted into the holes formed to the partition plate means;
tube taking-out means for sequentially taking out one by one the U-shaped tubes grasped by the tube grasping means; and
tube feeding means for feeding the taken-out tubes toward the partition plate means and inserting the tubes into the holes of the partition plate means.
In preferred embodiments, the heat exchanging tube assembling apparatus further comprises a tube accommodating means in which a plurality of U-shaped tubes are accommodated and a tube mounting means on which the tube accommodating means are mounted and which is disposed to the working position. The tube accommodating means is a tube packing case which accommodates the U-shaped tubes lengthily in a lateral direction while keeping U-shaped curved portions of the tubes on bent end sides horizontally and which is opened upward and a plurality of types of the U-shaped tubes including U-shaped curved portions having different radii are disposed from an inside to an outside of the packing case in a plane and the U-shaped tubes whose curved portions have the same radius are piled up, respectively. The tube packing case is provided with load shift preventing tube spacers which are long in a lengthwise direction and are intermittently disposed as a fall-down preventing structure in the tube packing case in the lengthwise direction of the tubes to thereby section the respective tubes whose U-shaped curved portions have different radii.
The heat exchanging tube assembling apparatus further comprises rail means disposed on a floor on which the heat exchanging tube assembling apparatus is disposed and a pair of L-shaped frame members which are disposed to be movable on the guide means and by which the tube grasping means, the tube taking-out means and the tube feed means are supported through horizontal arms. The heat exchanging tube assembling apparatus further comprises a tube taking-out portion support arm disposed to be perpendicular to the horizontal arms on a horizontal plane at extreme ends of the horizontal arms and the tube grasping means and the tube taking-out means are supported to be rotatable by the taking-out portion support arm. The tube positioning means for setting the tubes at a position where the tubes are inserted by moving the tube horizontally and vertically and turning the U-shaped tubes about a horizontal axis thereof is composed of the pair of L-shaped frame members, the respective horizontal arms supported by the L-shaped frame members to be movable upward and downward, the taking-out portion support arm and a reversing beam turnably provided to the taking-out portion support arm.
The tube grasping means and the tube taking-out means constitute a set of a tube taking-out unit in operative combination thereof and a plurality sets of the tube taking-out units are disposed with an interval along a longitudinal direction of the taking-out portion support arm.
The tube grasping means includes a thin sheet-shaped hanger which is lowered and inserted into the tube accommodating means in an approximately vertical state and moved in a lateral direction so as to abut against one side surface of a group of the U-shaped tubes which are packed in the tube accommodating means in a manner piled up vertically in a row, a hook which projects from a lower end of the thin sheet-shaped hanger in a lateral direction and is inserted below a lowermost tube, and a support arm which is disposed in parallel with the hanger and which abuts against another side surface of the group of the tubes in a vertical state and clamps the group of the tubes between the tubes and the hanger by locking the lower end thereof to the hook. The hook is turned in a direction where extreme ends of the hanger and the support arm are released. The tube taking-out means includes a pushing piece for pushing the plurality of tubes grasped by the hanger of the tube grasping means and the support arm thereof to a side of the hook at the extreme ends of the hanger and the support arm, a pushing cylinder for driving the pushing piece, a grooved roller for supporting a single tube positioned on the hook side from the lower side thereof, a link for supporting the grooved roller, and a cylinder unit for moving the link in a vertical and lateral directions to thereby cause said link to take out the tube supported by the grooved roller in a state that the hook is turned to release the extreme ends of the hanger and the support arm. The grooved roller for supporting the tube from the lower side thereof and the link for supporting the grooved roller are supported to be rotatable by a shaft at a tube taking-out position and usually disposed at the tube taking-out position by a spring and when a U-shaped curved portion of the U-shaped tube passes at the tube insertion time, the grooved roller and the link are operated to escape in a tube inserting direction through the shaft.
The tube feeding means includes a base, a roller support frame supported by the base to be movable upward and downward, a guide roller supported by the roller support frame and receiving the extreme end of the tube through a reciprocation of the guide roller along the tube inserting direction, and feeding drive rollers and follower rollers which are disposed downstream of the tube inserting direction of the guide roller of the roller support frame and rotated so as to clamp the tube to thereby feed the tube to the partition plate means of a heat exchanger.
The tube feeding means includes an introduction mechanism having an air chuck for introducing the tube from the tube taking-out means to the positions of the drive rollers and the follower rollers through the reciprocating movement thereof in the tube inserting direction together with or in place of the guide rollers. The tube feeding means includes a cylinder unit for pushing the U-shaped bent end side of the tube to the side of the partition plate means. The tube feeding means may further include a force gauge provided to the cylinder unit for pushing the bent end of the U-shaped tube.
A taper-shaped cap having a sharp extreme end is mounted to an open end side of the U-shaped tube and a guide member is provided to a lower portion of the hole formed to the partition plate means so as to guide the cap into the hole.
The tube grasping means includes self-determination means for automatically determining a position where a subsequent tube is grasped and taken out the subsequent tube in accordance with a position at which an initial tube is grasped and taken out at a tube grasping position.
The tube feeding means includes control means for self-determining a position where the tube is inserted into the hole of the partition plate means in accordance with a work data to thereby automatically determine the position where the respective tubes are inserted.
The tube grasping means, the tube positioning means, the tube taking-out means and the tube feeding means include operation sections, respectively, and at least one of the operation sections is provided with an element for achieving an abnormal load detecting function, an abnormal load automatic avoiding function or an emergency stop function.
The tube feeding means includes a speed detection means for detecting an operating speed of a tube to be fed therefrom.
According to the present invention, there is provided, in another aspect, a heat exchanging tube assembling method for a heat exchanger having an outer casing in which is arranged partition plate means formed with holes through which heat exchanging tubes, each having a U-shape in an outer appearance, are inserted from an open end side of the casing in a full automatic manner, the heat exchanging tube assembling method comprising the steps of:
taking out each predetermined number of the U-shaped tubes disposed in an accommodation place;
stocking the taken-out tubes to a stock position sequentially at a predetermined inserting portion from which the tubes are inserted into the holes of the partition plate means; and
sequentially taking out the stocked tubes from the stock position one by one and inserting the tube into the holes of the partition plate means, thus assembling the heat exchanging tubes in a predetermined fashion.
In the preferred example in this aspect, the U-shaped tubes includes a plurality of groups thereof having curved portions of different radii from each other, and the holes of the partition plate means are formed into a plurality of groups divided so as to correspond to the groups of the U-shaped tubes so that the tube groups are inserted into corresponding groups of the holes, the U-shaped tubes having different radii being disposed inside to outside in a horizontal plane and having the same radius being piled vertically in the the accommodation place and after all the tubes belonging to one group are inserted into the corresponding holes, the setup of a next group U-shaped tubes is achieved.
When the U-shaped tubes are taken out from the accommodation place, the U-shaped curved portions of the tubes on the bent end side are kept horizontally, the U-shaped curved portions are kept vertical at the position where the tubes are stocked and respective groups of the tubes whose U-shaped curved portions each has a smaller radius are sequentially inserted into the holes of the partition plate means. A plurality of heat exchangers are disposed in parallel with each other and the tubes are assembled to the heat exchangers in parallel or sequential manner. The U-shaped tubes are disposed in a packing case in which the U-shaped tubes having different radii are disposed and the packing case is introduced to a working portion and removed therefrom by using a conveyer.
In further aspects, there is provided a heat exchanging tube feed apparatus for a heat exchanger for taking out one by one a plurality of heat exchanging tubes each having a U-shape in an outer appearance and arranged in parallel with each other and feeding the tubes in one direction, comprising:
pushing means for pushing out the heat exchanging tubes;
a push-out cylinder for driving the push means for pushing out the heat exchanging tubes;
a grooved roller supporting one tube positioned to a lower side of the tubes from a lower side thereof;
a link mechanism supporting the grooved roller; and
cylinder means for driving the link mechanism vertically and horizontally and taking out sideway the tub supported by the grooved roller.
The grooved roller for supporting the tube from the lower side thereof and the link mechanism for supporting the grooved roller are supported to be rotatable by a shaft at a tube taking-out position and usually disposed at the tube taking-out position by a spring and when a U-shaped curved portion of the U-shaped tube passes at the tube insertion time, the grooved roller and the link mechanism are operated to escape in a tube inserting direction through the shaft.
A heat exchanging tube feed apparatus for a heat exchanger for feeding out the heat exchanging tube, received at a predetermined position, in one direction, comprising:
a base;
a roller support frame supported by the base to be movable upward and downward;
a guide roller supported by the roller support frame and receiving an extreme end of the tube through a reciprocation of the guide roller along the tube inserting direction; and
drive rollers and follower rollers which are disposed downstream of the tube inserting direction of the guide roller of the roller support frame and rotated so as to clamp the tube to thereby feed the tube to the heat exchanger.
The heat exchanging tube feeding apparatus may further comprise an introduction mechanism having an air chuck for introducing the tube to positions of the drive rollers and the follower rollers through reciprocating movement thereof in the tube inserting direction together with or in place of the guide rollers.
A heat exchanging tube feed apparatus for a heat exchanger for feeding the heat exchanging tube, received at a predetermined position, in one direction may comprise a speed detection means for detecting an operation speed of the tube to be fed.
According to the embodiment of the present invention of the structures and characters described above, the following functions and advantageous effects will be attained.
Conventionally, when a job which is executed using a crane is needed in a heat exchanging tube assembly job, since the tube assembly job depends on how other jobs are proceeded, there is a possibility that an idle time is caused to the tube assembly job itself. According to the embodiment, however, such an adverse affect does not arise and a working time can be saved because of the automatic assembling operation. Further, since the tube grasping means, which can directly take out a necessary number of the tubes from the tube accommodation means such as packing case is provided for the assembling apparatus, a hanging-down job or operation by a crane is not necessary while the tubes are inserted. Thus, a job using the crane can be minimized and a working process can be also shortened.
Since the two packing cases are loaded on the mounting member, the tubes to be accommodated therein can be packed by being separated to those used to odd stages and those used to even stages and thus the tubes for the alternate stages can be accommodated in the same case. Regardless of this arrangement, the gaps between the respective tubes are very narrow and further since the tubes are long, they are irregularly disposed in a lengthwise direction and the gaps are greatly dispersed. Since the tube grasping means is provided with a function which enters the narrow portions and shoves the tubes and a tube lifting mechanism to cope with this problem, the tubes can be naturally taken out from the packing case.
Since the tubes have a small diameter and a long entire length, when the tubes left in a piled-up state are lifted up, they are liable to cause a load shift. Whereas, since the support arm is added to the hanger as a countermeasure for preventing the load shift in the tube grasping means, when the tube grasping means is provided with a multiplicity of units having the same mechanism, it can reduce a load applied on a single unit, by which the size of the unit itself can be reduced.
Since the base portion of the apparatus is arranged as the cantilever arm type by the employment of the L-shaped frames, the packing case can be set up in the state that one side of the apparatus is opened. Thus, the frames do not obstruct operation and a space can be saved. As to the inserting job of the tubes, the tubes which have been taken out and placed at a stock position can be securely taken out one by one by the tube taking-out means and effectively and securely inserted by the tube feed-out means and the insertion of the tubes can be securely completed. Further, since the apparatus of the embodiment can be divided into several units, the apparatus can be accommodated by being divided into the units when it is not used, by which a storing space can be minimized.
According to the method of the present invention, the tube assembly job can be carried out in a necessary minimum space in such a manner that after the tubes accommodated in a necessary minimum number of the packing cases are inserted into all the holes of the partition plates, the setup of the packing cases is changed and the tubes in the next packing cases are assembled. Since a portion of the mechanisms can retract when the tube is fed to the partition plates, even if the U-shaped curved portion at the rear end of the tube is fed during tube inserting, feeding of the tube is free from obstruction by retracting the mechanisms. Thus, the tube insertion job can be smoothly carried out.
Further, since there is provided the control mechanism which determines the position where the tube is inserted by itself based on workpiece data previously input to move and feed the tube, the control mechanism can determine the position of the next tube from the position of the tube fetched first and take out the tube. In addition, since the function for detecting an abnormal load, the occurrence of an accident can be previously prevented and safety can be improved.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions with reference to the accompanying drawings.